Nowadays, magnetic elements such as inductors and transformers are widely used in many electronic circuits to generate induced magnetic fluxes. Many conventional magnetic elements have magnetic core assemblies to form induced magnetic flux path. Depending on the material and the shapes of the magnetic core assembly, the magnetic properties of the magnetic elements are varied.
Referring to FIG. 1, a conventional transformer including a magnetic core assembly and multiple winding coils is schematically illustrated. The transformer 1 of FIG. 1 comprises a magnetic core assembly 10 and several winding coils including for example a primary winding coil 11, a first secondary winding coil 12 and a second secondary winding coil 13. The magnetic core assembly 10 includes a first side plate 101, a second side plate 102, a first side pillar 103, a second side pillar 104 and a middle pillar 105. The first side pillar 103, the second side pillar 104 and the middle pillar 105 are substantially parallel to each other, and perpendicular to the first side plate 101 and the second side plate 102. The first side pillar 103 and the second side pillar 104 are arranged on bilateral edges of the first side plate 101 and the second side plate 102. The middle pillar 105 is arranged between the first side pillar 103 and the second side pillar 104. The primary winding coil 11 is wound around the first side pillar 103 and the second side pillar 104 of the magnetic core assembly 10. For example, the primary winding coil 11 is wound around one of the first side pillar 103 and the second side pillar 104 and then wound around the other one of the first side pillar 103 and the second side pillar 104. The first secondary winding coil 12 is wound around the first side pillar 103 and separated from the primary winding coil 11. The second secondary winding coil 13 is wound around the second side pillar 104 and separated from the primary winding coil 11. A first terminal of the first secondary winding coil 12 is coupled with a first terminal of the second secondary winding coil 13 at a node “d”. The magnetic core assembly 10 interacts with the winding coils 11, 12 and 13 to provide a closed magnetic flux path. When the current flowing through the primary winding coil 11 has a variation, sensing currents are generated in the first secondary winding coil 12 and the second secondary winding coil 13 due to magnetic coupling.
As known, the high assembling tolerance of the magnetic core assembly 10, the large leakage flux and the lengthy winding coils contribute to a considerable winding loss of the transformer 1. On account of high operating efficiency and low power consumption, such a transformer 1 is not feasible.
Therefore, there is a need of providing a magnetic element having reduced winding loss.